Early
Spay / Neuter in the Cat
An Article Written by: Susan Little DVM - A Winn Feline Foundation
Report
|
|
|
|
|
|
Is Early
Desexing of Kittens Safe? 
|
|
|
|
|
|
|
While it may seem that interest in early spay/neuter is a
recent phenomenon, it has not only been talked about, but it has been practiced for over 25 years in North
America. Early age altering refers to spays and neuters done between the age of 6 and 14 weeks. Altering pets
between 5 and 7 months of age was established by tradition rather than for any specific medical reason. Years
ago, when safe paediatric anaesthetic techniques were not available, waiting until a patient was older
increased the safety of surgery. But we no longer need to delay altering for this reason.
People working to decrease the problem of surplus dogs and cats in the United
States pioneered the idea of early altering. While surgical sterilization remains the most effective means of
population control, delaying the surgery long enough for sexual maturity to occur defeats the purpose. Animal
shelters advocate mandatory altering, but many adopted animals either are never altered or have at least one
litter first.
Over the years, the safety of early altering has been questioned, mainly by
veterinarians who may be unfamiliar with the surgical and anaesthetic techniques required for paediatric
patients. As well, concerns that early altering could increase the incidence of feline lower urinary tract
disease, could affect skeletal development, and affect behaviour have been voiced. These concerns have largely
been laid to rest by many studies, and early altering is becoming more widespread and available. A study
recently published by researchers at the University of Florida found no significant differences in the physical
and behavioural characteristics of cats altered at 7 weeks of age compared to those altered at 7 months of
age.
Very important work has been done by Drs. Michael Aronsohn and Alicia Faggella at
the Massachusetts SPCA on the anaesthetic and surgical techniques for early altering of dogs and cats. In 1993,
two papers were published outlining their work on the early altering of hundreds of kittens between the age of
6 and 14 weeks. They evaluated several anaesthetic protocols and made recommendations for safe handling and
anaesthesia in patients of this age. Some small changes to surgical technique are necessary for patients in
this age group. As well, these young patients must be handled a bit differently both before, during, and after
surgery. The changes in surgical protocol are simple and easy to carry out, and the experience of these
veterinarians with early altering is overwhelmingly positive.
As cat breeders, we must do our part to curtail the serious issue of surplus
animals. Many of us work in breed rescue programs and give our time and expertise to shelters. We can ensure
that our own kittens not destined for breeding programs will never reproduce by practicing early altering.
Early altering is a safe and effective means of ensuring we do not unwittingly add to the burden of unwanted
pets.
Further information - refer to the website for The Winn Feline
Foundation.
# A progress report on a study funded by The Winn Feline
Foundation - Developmental and Behavioral Effects of Prepubertal Gonadectomy. Mark S. Bloomberg, DVM, MS; W.P.
Stubbs, DVM; D.F. Senior, BVSc; Thomas J. Lane, BS, DVM; University of Florida at Gainesville. Funded by the
Winn Feline Foundation, February 1991. Continuation funded - Summary prepared by Diana Cruden, Ph.D.
Background and medical issues including a summary of an ongoing Winn Foundation
funded project to evaluate the long term effects of early altering.
The concept of early spaying and neutering (e.g. before the animal is sexually
mature) is not a new one. In the early 1900's, early neutering was the norm and it was not until much later
that questions were raised about the negative side effects of such a procedure. Today most of the experts
acknowledge that there has not been enough scientific information available about the most appropriate age to
neuter a pet. Until recently, there was no research data that either supported or disproved the idea that
neutering dogs and cats at ages younger than five to eight months was deleterious.
There is, in fact, little scientific basis for selecting this age group as the
most appropriate time for neutering. Indeed, one investigator points out that many veterinarians have been
practicing early neutering for years, since there is an incredible range of ages when puppies and kittens reach
sexual maturity. Large animal practitioners have long practiced early neutering on their livestock and consider
it not only acceptable, but desirable in many cases.
Even before concerns for the burgeoning population of unwanted pets raised our
collective consciousness, there were many scientifically documented reasons to spay and castrate.
Spayed females are protected against mammary cancer and uterine infections. In
males, castration reduces the risk of testicular cancer and enlargement of the prostate and related infections.
From the pet owners point of view, the spayed or castrated pet is a much better companion. They are less
aggressive and more affectionate than their unaltered counterparts. Since they are not driven by the urge to
reproduce, they are less likely to roam and fight.
Controlled studies into the short- and long-term effects
Controlled studies into the short- and long-term effects of early neutering have
been sadly lacking until recently. While there had been numerous anecdotal reports of early spaying and
neutering, these cases were generally uncontrolled from the scientific viewpoint. Most reported cases were
random bred, unrelated animals from a variety of backgrounds and no attempt was made to control for these
variations. There have been few university based studies in this area. M.A. Herron of Texas A&M reported in
1972 that neutering before sexual maturity had relatively little effect on the diameter of the urethra in male
cats.
Studies have more recently been conducted at Angell Memorial Hospital in Boston,
the College of Veterinary Medicine at the University of Minnesota, and the Department of Small Animal Clinical
Sciences at the University of Florida.
The Florida research project
The Florida project, begun in 1991 and completed in 1992, was funded by the Winn
Feline Foundation in conjunction with the American Veterinary Medical Association (AVMA). A serious attempt was
made in this study to limit background influences and genetic variation.
The kittens were bred especially for the project and litter mates were divided
among the three groups. The queens were bred and housed in quarantined facilities since both pre- and
post-natal nutrition and other factors can contribute to the ultimate size, weight, and overall health of the
kittens. Dr. Mark Bloomberg indicates that although long-term follow-up results are incomplete, the initial
results are extremely positive. Prior to undertaking the Winn Foundation study, Dr. Bloomberg had completed a
similar study in dogs. Animals involved in that study have now been followed for over five years, with no
negative side effects reported. In the Winn Foundation study, there were a total of 31 domestic shorthair
kittens from 7 litters born on the Gainesville campus.
The kittens were divided into three groups:
* Group 1 (11 kittens) were neutered or spayed at 7 weeks of
age.
* Group 2 (11 kittens) were neutered or spayed at 7 months.
* Group 3 (the control group of 9 kittens) were not neutered until maturity
and after the completion of the first phase of the study at 12 months.
The investigators reported that the surgical procedures in the Group 1 kittens
were straightforward and uncomplicated, and that the kittens recovered even more rapidly than the Group 2
kittens and Group 3 cats. Dr. Bloomberg notes that although there is very little material on paediatric
anaesthesia in animals, the paediatric patient in human medicine is generally considered to be a very good
surgical candidate and there is no reason why this should not also be true for dogs and cats.
The major concerns in paediatric surgery are:
* preventing hypothermia (maintaining body heat);
* utilizing proper doses of anaesthetic agents (since the respiratory
centres are not as well developed in the paediatric patient); and
* maintaining proper blood glucose.
The investigators did not fast the paediatric patients as
long as adult patients and administered small amounts of Karo syrup prior to induction of anaesthesia as a
precaution. It should be noted that due to the rapid recovery of the paediatric patient, the common practice of
reducing anaesthesia during final stages of the surgery was modified.
Critics have claimed several possible detrimental side effects from early
neutering. It is commonly believed that neutered animals are less active and more prone to obesity than
unaltered animals. It was also suggested that neutering at an early age would stunt normal growth. In male cats
in particular, it was feared that early castration would affect the development of the urinary tract and lead
to an increased incidence of cystitis or urinary obstruction. Concerns have also been raised as to the effect
of early neutering on behaviour, food consumption and dietary requirements, etc. The investigators attempted to
answer most of these questions by evaluating several parameters in the three groups of kittens. In particular,
they looked at weight and body composition (i.e., percent of body fat); bone length and the age of physeal
closure (the age when long bone growth stops); behaviour; food consumption; development of the urinary tract;
and the development of secondary sexual characteristics and degree of sexual maturity.
The results of the comparisons of weight showed some differences between the
three groups. Males weighed consistently more than females, but this was uniform in all groups. The studies of
body composition and body fat indicated that Group 1 (neutered at 7 weeks) and Group 2 (neutered at 7 months)
were identical and were generally fatter than Group 3 (neutered at 12 months, after they were sexually mature).
Investigators point out that by 12 months, the male cats in Group 3 were already exhibiting the normal adult
male characteristics of decreased weight and the development of jowls, which accounts for some of the
differences. It has also been noted that in the course of follow-up, the differences between the weight in cats
from Group 1 and 2 and Group 3 are becoming less apparent. All these cats have been placed in selected and
supervised pet homes and are more active than they were in the University facilities. A three-year follow-up
exam was to be conducted in May of 1994.
Observations
* Growth rates
There was generally no difference in food consumption between the three groups
other than the differences between males and females, which were consistent in all groups. There was no
difference observed in the growth rates in all three groups, although the males grew faster in all groups.
Increased long bone length was observed in both males and females in Groups 1 and 2. This appeared to be due to
the fact that physeal closing (closure of the bone growth plate) was delayed in Groups 1 & 2. This explains
why cats neutered and spayed as kittens are frequently larger (longer and taller) than unaltered cats or cats
altered later in life. This seems to be particularly true for males.
* Behavioural differences
In terms of behaviour, after 7 months, the cats in Group 3 were noticeably less
affectionate and more aggressive prior to altering than the cats in Groups 1 and 2. Contrary to popular
opinion, neutered animals were as active as their unaltered age mates.
* Urinary tract development, sexual characteristics
Observations of urinary tract development showed no differences between the three
groups other than the differences related to sex and these were consistent across all groups.
The investigators measured the diameter of the urethra in the male kittens only
and found no differences between the groups. Concerns have been raised that early neutering would result in
smaller diameters in the urinary tract, resulting in an increased incidence of cystitis and related problems.
This does not appear to be the case. The main differences observed between the groups occurred in the
comparison of secondary sex characteristics. Males were examined for differences in the development of the
penis and prepuce (skin covering the penis), as well as for the development of penile spines. The penile spines
were absent in Group 1, smaller than normal in Group 2, and normally developed in Group 3. In the examination
of the female kittens, investigators found that the vulvas were more infantile in Groups 1 and 2 and normal in
Group 3. None of these differences had any impact on the ability to catheterise the kittens. Concerns that
development of the urinary tract might be arrested or impaired by early spaying and neutering proved
unsupported.
Results of this study
The results of this study so far indicate that the
differences between cats neutered at 7 weeks and 7 months are insignificant. The differences observed between
animals in Groups 1 and 2 and the animals in Group 3, while in some cases statistically significant, are not
differences which appear to affect the health of the animal in a negative way. While the final results will
depend on the analysis of long-term follow-up, the indications are that early neutering is not detrimental to
the overall health of the animal. From the perspective of shelters and particularly in respect to the problem
of surplus puppies and kittens these results are encouraging. If all the animals adopted from shelters,
including puppies and kittens, are neutered prior to adoption, there should be a corresponding decrease in the
numbers of animals euthanised each year in this country. Preliminary results from Alachua County, near the
University of Florida at Gainesville, would seem to support this theory.
Alachua County Animal Control has been working with the investigators at the
University and have had an early neuter policy in place since 1990. No animal leaves the shelter without being
neutered. In 1987 the county euthanised 1,250 cats and dogs per month. Since implementing the early neuter
policies they have seen the numbers drop to 940 per month in 1992 and there has been no increase in morbidity
or mortality associated with the program.
In the last year, recognition of the safety and efficacy of early spay/neuter has
grown rapidly. The American Humane Association has endorsed early neutering prior to adoption as a "feasible
solution to decreasing pet overpopulation and the tragedy of resulting deaths." In July 1993, delegates to the
American Veterinary Medical Association Annual Meeting voted to give AVMA's support to the concept of early
neutering. Work done by veterinarians at Angell Memorial Hospital for the Massachusetts Society for the
Prevention of Cruelty to Animals supports Dr. Bloomberg's observations. Other organizations involved in early
neuter programs include the Denver Dumb Friends League in Colorado, the Miami Humane Society and Alachua County
Animal Control in Florida, The Humane Society of Austin and Travis County in Texas, the Chicago Animal Control
in Illinois, the King County Animal Control in Washington state, the Vancouver SPCA in British Columbia and the
Southern Oregon Humane Society in Oregon. The Dekalb Humane Society in Decatur, Collie Rescue of Metro Atlanta,
the Georgia Alliance of Purebred Canine Rescuers, The Haven (dog rescue) and Dog River Sanctuary in
Douglasville are among the Georgia organizations working with early neuter in dogs and cats, as well as exotic
species.
The Cat Fanciers' Association (CFA) has changed its show rules to permit altered
kittens to compete. Many breeders of pedigreed cats are working with their veterinarians to neuter pet quality
kittens prior to placement in new homes. Those breeders who have adopted this policy report that they are very
happy with the practice. New pet owners indicate that acquiring an already neutered animal relieves them of the
worry and expense of scheduling the surgery at a later date, enabling them to relax and enjoy their new
companion. As is the case for shelter managers, breeders can relax in the knowledge that the kitten they place
today is not going to contribute to the surplus pet population tomorrow.
Further information - refer to the website for The Winn Feline
Foundation
|